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Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

1,261.

Consider the reaction represented by the following equation: C2H2 + yH2 → C2H6. The value of y in the reaction is

A.

4

B.

3

C.

2

D.

1

Correct answer is C

C2H2 + yH2 → C2H6

To balance the equation, we must have 2 carbon atoms on both sides and 6 hydrogen atoms.

On the LHS and RHS, carbon = 2 atoms.

On the LHS, Hydrogen = 2 + 2y.

On the RHS, Hydrogen = 6.

⇒ 2 + 2y = 6

2y = 4

y = 2.

1,262.

Which of the following statements about nuclear reaction is correct? The reaction

A.

involves neutrons only

B.

takes place inside the nucleus

C.

is governed by temperature and pressure

D.

involves protons and electrons only

Correct answer is B

A nuclear reaction is semantically considered to be the process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides.

1,263.

Noble gas molecules are held together by

A.

van der Waals forces

B.

hydrogen bonds

C.

dative bonds

D.

covalent bonds

Correct answer is A

No explanation has been provided for this answer.

1,264.

Which of the following elements is diatomic?

A.

Sodium

B.

Oxygen

C.

Iron

D.

Neon

Correct answer is B

The seven diatomic elements are Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Iodine, Bromine. 

1,265.

The bonds in crystalline ammonium chloride are

A.

covalent and dative

B.

ionic and covalent

C.

ionic, covalent and dative

D.

ionic, covalent and hydrogen bond

Correct answer is C

N makes three covalent bonds with three Hydrogen and a coordinate (dative covalent) bond with with hydrogen ion, forming ammonium ion (NH+4. The ammonium ion forms an ionic bond with chloride ion to form NH4Cl.